The Flesch-Kincaid Index provides a readability estimate of how easy it is to read and understand the text of a book.

It is a refinement to the Flesch index and tries to relate the score to a U.S. grade level. For example, text with a Flesch-Kincaid score of 10.1 would be considered suitable for someone with a 10th grade or higher reading level.

Scanned copies of books are be read by a computer programme and the score assigned.